Advertisements
Advertisements
Question
If class mark is 10 and class width is 6 then find the class.
Advertisements
Solution
Let x be the upper class limit and y the lower class limit.
class mark = 10 ..[given]
class mark = `(x + y)/2`
10 = `(x + y)/2`
x + y = 20 ...(i)
class width = 6 ...[given]
x - y = 6 ....(ii)
Adding equation (i) and (ii)
x + y = 20
+ x - y = 6
2x = 26
x = `26/2`
x = 13
Putting the value x = 13 in equation (i),
x + y = 20
13 + y = 20
y = 20 -13
y = 7
∴ the class is 7-13.
APPEARS IN
RELATED QUESTIONS
Complete the Following Table.
| Classes (age) | Tally marks | Frequency (No. of students) |
| 12-13 | `cancel(bb|bb|bb|bb|)` | `square` |
| 13-14 | `cancel(bb|bb|bb|bb|)` `cancel(bb|bb|bb|bb|)` `bb|bb|bb|bb|` | `square` |
| 14-15 | `square` | `square` |
| 15-16 | `bb|bb|bb|bb|` | `square` |
| N = ∑f = 35 |
In a village, the milk was collected from 50 milkmen at a collection center in litres as given below:
27, 75, 5, 99, 70, 12, 15, 20, 30, 35, 45, 80, 77, 90, 92, 72, 4, 33, 22, 15, 20, 28, 29, 14, 16, 20, 72, 81, 85, 10, 16, 9, 25, 23, 26, 46, 55, 56, 66, 67, 51, 57, 44, 43, 6, 65, 42, 36, 7, 35.
By taking suitable classes, prepare grouped frequency distribution table.
The monthly maximum temperature of a city is given in degree celcius in the following data. By taking suitable classes, prepare the grouped frequency distribution table
29.2, 29.0, 28.1, 28.5, 32.9, 29.2, 34.2, 36.8, 32.0, 31.0, 30.5, 30.0, 33, 32.5, 35.5, 34.0, 32.9, 31.5, 30.3, 31.4, 30.3, 34.7, 35.0, 32.5, 33.5, 29.0, 29.5, 29.9, 33.2, 30.2
From the table, answer the following questions.
- For how many days the maximum temperature was less than 34oC?
- For how many days the maximum temperature was 34oC or more than 34oC?
Construct the frequency distribution table from the following cumulative frequency table:
| Ages | No. of students |
| Below 4 | 0 |
| Below 7 | 85 |
| Below 10 | 140 |
| Below 13 | 243 |
| Below 16 | 300 |
(i) State the number of students in the age group 10 - 13.
(ii) State the age-group which has the least number of students.
Construct a frequency distribution table from the following cumulative frequency distribution:
| Class Interval | Cumulative Frequency |
| 10 - 19 | 8 |
| 20 - 29 | 19 |
| 30- 39 | 23 |
| 40- 49 | 30 |
In a certain colony, there are 50 families. The number of people in every family is given below. Draw up the frequency table.
5, 4, 5, 4, 5, 3, 3, 3, 4, 3, 4, 2, 3, 4, 2, 2, 2, 2, 4, 5, 1, 3, 2, 4, 5, 3, 3, 2, 4, 4, 2, 3, 4, 3, 4, 2, 3, 4, 5, 3, 2, 3, 2, 3, 4, 5, 3, 2, 3, 2
The upper limit of the class interval (25 - 35) is _____________
Represent the following data in ungrouped frequency table which gives the number of children in 25 families.
1, 3, 0, 2, 5, 2, 3, 4, 1, 0, 5, 4, 3, 1, 3, 2, 5, 2, 1, 1, 2, 6, 2, 1, 4
Form a continuous frequency distribution table for the marks obtained by 30 students in a X std public examination.
328, 470, 405, 375, 298, 326, 276, 362, 410, 255, 391, 370, 455, 229, 300, 183, 283, 366, 400, 495, 215, 157, 374, 306, 280, 409, 321, 269, 398, 200
The number of times an observation occurs in the given data is called ________
Size of the class 150 – 175 is ______.
Tally marks are used to find ______.
In the class interval 20 – 30, the lower class limit is ______.
In the class interval 26 – 33, 33 is known as ______.
Using the following frequency table.
| Marks (obtained out of 10) | 4 | 5 | 7 | 8 | 9 | 10 |
| Frequency | 5 | 10 | 8 | 6 | 12 | 9 |
The frequency of less than 8 marks is 29.
Using the following frequency table.
| Marks (obtained out of 10) | 4 | 5 | 7 | 8 | 9 | 10 |
| Frequency | 5 | 10 | 8 | 6 | 12 | 9 |
The frequency of more than 8 marks is 21.
The weights (in kg) of 30 students of a class are:
39, 38, 36, 38, 40, 42, 43, 44, 33, 33, 31, 45, 46, 38, 37, 31, 30, 39, 41, 41, 46, 36, 35, 34, 39, 43, 32, 37, 29, 26.
Prepare a frequency distribution table using one class interval as (30 – 35), 35 not included.
- Which class has the least frequency?
- Which class has the maximum frequency?
Complete the following table:
| Weights (in kg.) |
Tally Marks | Frequency (Number of persons) |
| 40 – 50 | `\cancel(bb|bb|bb|bb|) \cancel(bb|bb|bb|bb|) bb|bb|` | |
| 50 – 60 | `\cancel(bb|bb|bb|bb|) \cancel(bb|bb|bb|bb|) bb|bb|bb|bb|` | |
| 60 – 70 | `\cancel(bb|bb|bb|bb|) bb|` | |
| 70 – 80 | `bb|bb|` | |
| 80 – 90 | `bb|` |
Find the total number of persons whose weights are given in the above table.
